In the statement cited by Mr Trump, the North Korean government referred to Vice President Mike Pence as a "political dummy" and said it is just as ready to meet in a nuclear confrontation as at the negotiating table.

Mr Trump told Mr Kim "please do not hesitate to call me or write" should he change his mind about a one-on-one meeting.

A letter from the President to Chairman Kim Jong Un: "It is inappropriate, at this time, to have this long-planned meeting." pic.twitter.com/3dDIp55xu1
— The White House (@WhiteHouse) May 24, 2018